**7. Qualitative and quantitative mica protein expression as toxicological stress marker of the immune system**

Cetacean morbilliviruses and papillomaviruses as well as *Brucella* spp. and *Toxoplasma gondii* are thought to reduce population abundance by inducing high mortalities, lowering reproductive success or by synergistically increasing the virulence of other diseases. Severe cases of lobomycosis and lobomycosis-like disease (LLD) may contribute to the death of some dolphins [37]. Environmental contamination seems to play a role in these diseases because many pollutants are known immunosuppressants and can markedly affect the immune status of the cetacean specimens [38, 39, 40, 41, 42]. As already mentioned, the cetacean skin is an important tissue of the immune system and the MICA protein, used in this study as toxicological stress marker of the immune system, is expressed in fibroblasts. In fact, the aim of this study was to evaluate the MICA protein expression in fibroblast cell cultures of cetaceans (skin biopsies of free-ranging animals and skin samples of stranded cetaceans dead within 2-12 h). Here we present the immunofluorescence technique in cultured fibroblasts used for qualitative and quantitative evaluation of MICA expression, induced by treatment with OC mixture, flame retardants, PAHs and BPA, as toxicological stress marker of the immune system of different species of odontocetes (sperm whale (PMAS1)*,* killer whale (OO12), striped dolphin (RT23), long-beaked common dolphin (MDC12)) and mysticetes (fin whale (RT25)*,* Bryde's whale (MBE3)).
